A British newspaper and a rights group founder say police are investigating an alleged plot by disgruntled activists to briefly abduct Prime Minister Tony Blair's 5-year-old son Leo to highlight their cause.

The Sun newspaper claimed the plan was made by a group campaigning for better rights for fathers denied access to their children.

The British Broadcasting Corp. reported that police said they knew of suggestions of such a plot, but were not convinced that those involved had the ability to carry it out. The BBC said there was no kidnapping attempt and no arrests made.

Blair's Downing Street office told The Associated Press "we are not going to comment on this story." London's Metropolitan police said "we are not prepared to discuss matters of security of this type."

The Sun, quoting an unnamed security source, claimed police officers had uncovered the plot while probing activities of members of the Fathers 4 Justice movement.

That group's founder told the AP that the purported plot has "definitely nothing to do with the official group."

Matt O'Connor said that anti-terrorism police had been investigating some former members of his group.

"I was made aware in December that anti-terrorist branch were involved and when I checked, that was correct," he said.

"If there are extremists on the fringes who could undermine all the work we have done, we would have to consider our positions and perhaps think about winding the group up."

Blair and his wife Cherie also have sons Euan, 21 and Nicholas, 20, and daughter Kathryn, 17.